1. Field of the Invention
The present invention relates to a fractionation process of the unsaponifiable material derived from black-liquor soaps of the cellulose industry. Through this procedure fractions that essentially contain free sterols, fatty alcohols, sterol esters and fatty alcohol esters respectively are separated. Fractions containing sterols or fatty alcohols can be used as such in the alimentary, cosmetic and pharmaceutical industries or they can be used as raw materials for transforming into other useful products.
2. Description of the Related Art
Black-liquor soaps are by-products of the Kraft pulping process of pine and other woods. Typically, during the Kraft process, wood chips are digested or cooked for two hours at 170xc2x0 C. in an aqueous liquor containing sodium hydroxide and sodium sulfide. The digestion delignifies the wood chips and gives rise to a dark aqueous suspension called black liquor which along with lignin contains cellulose pulp, sodium soaps of rosin acids and fatty acids, a series of neutral organic compounds such as sterols, terpene, fatty alcohols, sterol esters, fatty alcohol esters and products of lignin degradation. Under these conditions, the cellulose is stable and remains in suspension in the black liquor. When the pulping process reaction is finished, the cellulose pulp is separated from the black liquor and is washed. The pulp can be used as such or exposed to further purification processes.
The black liquor must be recovered for both economics and environmental reasons. To this end, the black liquor is typically concentrated by evaporation to a solid content from 23 to 32% in weight of black liquor solids. This causes the separation of fatty acid soaps and rosin soaps and also other hydrophobic compounds solubilized in the soaps. The soaps float at the top of the vessel where they are removed or skimmed off, hence they are called xe2x80x9cskimmingxe2x80x9d. Skimming is the term that we are going to use as a synonym of black liquor soaps. Other names used to denominate this fraction are xe2x80x9ctall oil soapxe2x80x9d or xe2x80x9cCSSxe2x80x9d (Crude Sulfate Soap).
The skimming contains ordinarily between 30 and 50% of water. The skimming solids are a complex mixture of sodium fatty soaps and rosin acids, and a series of hydrophobic substances essentially composed of sterols, stanols, fatty alcohols, diterpenoids, sterol esters and fatty alcohol esters with fatty acids. These hydrophobic compounds are known as the neutral unsaponifiable fraction or unsap. Sometimes these unsaps constitute up to 25% of the skimming solids.
The skimming may be used as fuel oil; its calorific value is lower than the half of the fuel oil calorific value. It may be upgraded by transforming into tall oil with sulfuric acid and separating the oil from the aqueous phase. This oil is known as crude tall oil (CTO). Then CTO is exposed to a series of vacuum distillations which produce: fatty acids, TOFA or Tall Oil Fatty Acids, (these are the most valuable product obtainable from CTO); rosin acids or TOR (Tall Oil Rosins); DTO or Distilled Tall Oil, which has many industrial uses and PITCH that is the bottom of the distillation, which is used as fuel or as an ingredient for the preparation of asphalt emulsions.
Until recently, improvement in CTO quality was the major reason for refining or separating the unsaponifiable fraction.
Nowadays, there has been a revaluation of unsaps as a source of important chemical products such as sterols, stanols, superior alcohols (notably docosanol and tetracosanol) and their respective esters. They are increasingly applied in the pharmaceutical, cosmetic and alimentary industry.
The refining processes of soaps and the extraction of neutral or unsaponifiable material are widely known in the state of the art and involve the extraction of unsaponifiable material with organic solvents, including supercritical solvents. However, fractionation procedures of these unsaps exhibit a series of technical and economic drawbacks.
Table I shows the average chemical composition of unsaps used in the present invention derived from skimmings of domestic cellulose industries.
The group of components called xe2x80x9cothersxe2x80x9d is mainly composed by terpenoids (mono and diterpenes and its by-products) and betulaprenols and an additional series of insufficiently characterized compounds.
Most identified components of unsaps in Table I are compounds of commercial interest. Sterols, either free or esterified, have many uses as raw material in the pharmaceutical, cosmetic and fermentation industries for transforming into steroids. Sterol esters have been revealed as important antitumor-like agents and their utilization for that purpose is described in U.S. Pat. No. 5,270,041. The reduced form sterols, or stanols, has an important application in the formulation of diets for the reduction of plasmatic cholesterol levels. The use of free stanols for that purpose appears in U.S. Pat. No. 5,244,887, and the utilization of ester stanols for the same purpose appears in U.S. Pat. No. 5,502,045.
There is an increasing interest about fatty alcohols, especially docosanol and tetracosanol, due to their notable pharmacological properties as both anti-inflammatory and antiviral agents. The use of these alcohols with pharmacological purposes appears in many US patents (U.S. Pat. Nos. 4,874,794; 3,031,376; 5,534,554; 5,071,879; and 5,166,219).
At present, the methods known for separating the valuable components of unsaps derived from black liquor soaps or skimming are, hardly without any exception, several variants to dissolution and recrystallization processes. One of the disadvantages of this technique is that it only allows recovering free sterols, remaining the valuable fatty alcohols and alcohol and sterol esters in the mother liquor and they can not be fractionated through liquor recrystallization. By this means, not only the valuable fatty alcohols are not used but also the sterol esters. As a cause of this, the sterol preparation obtained by the methods known in the state of the art is deprived of an important sterol that is mainly found in an esterified form in the unsaps (stigmasterol) and a significant quantity of stigmastanol and sitostanol. The latter is identified as one of the most active and important sterols in the reduction of plasmatic cholesterol levels as it is disclosed in the application PCT/CA95/00555 and U.S. Pat. No. 5,502,045.
To illustrate what was mentioned above, Table II shows the sterol composition in the unsap fraction composed by esters. Through the procedure of this invention described below, these esters are separated from other unsaps components, then they are hydrolyzed and exposed to a chromatographic analysis, resulting the following results:
The separation of the ester fraction from unsaps and its further hydrolysis surprisingly discloses the presence of sterols in the unsaps like stigmasterol which is not normally detected.
There are many patents that disclose the different methods of the unsap fractionation technique.
U.S. Pat. No. 4,044,031 discloses a dissolution method of unsaps in a solvent mixture, which includes hexane-acetone-methanol, followed by a process of liquid-liquid extraction using a hexane-acetone-water mixture. The extract is concentrated and then is cooled down to obtain a sterol concentrate through crystallization.
U.S. Pat. No. 4,420,427 discloses a method by which the unsaps are exposed to a hot dissolution with methyl ethyl ketone or with a mixture of methanol with methyl ethyl ketone. Then, by cooling down the mixture, a sterol precipitate separates and it is recovered from the mother liquor through filtration.
A variant to these methods is disclosed in U.S. Pat. No. 4,265,824. The unsaps are dissolved in an organic solvent, then a strong acid is added and this causes the formation of a compound with xcex1-sitosterol and then, by cooling down the mixture causes the precipitation of xcex2-sitosterol.
The separation of xcex2-sitosterol and fatty alcohols, from the pitch of tall oil by means of steam distillation at high temperature, between 190 and 280xc2x0 C., and the vacuum rectification of the vapor of these components have been disclosed in U.S. Pat. No. 2,866,739 of 1958 entitled Recovery of xcex2-sitosterol from tall-oil pitch by steam distillation.
Nevertheless, such procedure can not be applied to separate the different unsap components because it has many disadvantages such as the use of steam at high temperature along with a high thermal degradation and oxidation of its valuable components.
U.S. Pat. No. 4,263,103 discloses a procedure to remove ferric ions from sterol concentrates obtained from vegetable oil or tall oil through extraction and crystallization techniques. The presence of ferric ions in sterol concentrates has a negative catalytic effect on their stability.
Accordingly, it can be seen that the fractionation through short path distillation of the complex mixture of unsaps with a content of fatty alcohols, sterols and esters of these to produce concentrates is not known in the state of the art.
The fractionation procedure of unsaps described in the present invention provides for the separation of an enriched fraction of sterols, fatty alcohols and an ester fraction. It is a highly efficient procedure and it does not use organic solvents, which is an additional advantage if we consider the increasing environmental restrictions for using organic solvents.
Raw materials for fractionation process The raw material used in the fractionation process comprises the unsaponifiable skimming fraction mainly from domestic cellulose industries (CELPAC, ARAUCO, etc.) although it can also be applied to skimmings from any origin. The unsaps can be extracted through procedures known in the state of the art. When the unsaponifiable fraction is extracted with organic solvents, this fraction must first be desolventized before fractionation. The desolventation can be carried out by application of heat at normal pressure or preferably at reduced pressure.
The raw material of the present invention can also comprise desolventized and enriched unsaps formed through the addition of one or more fractions from the same separation procedure or from any derived product or by-product. Thus, for example, the ester fraction of unsaps, once separated from these unsaps, can be hydrolyzed and such hydrolyzed product can be added to the desolventized unsaps from the skimmings. Hereafter, the term xe2x80x9craw materialxe2x80x9d must be understood as desolventized unsaps. When the raw material is made up of enriched unsaps as described, the term xe2x80x9cenriched raw materialxe2x80x9d will be used.
For the purposes of the present invention, the complex raw material shown in Table I can be conveniently divided into three groups of components: (1) a group that mainly comprises fatty alcohols, diterpenes, diterpenoids and unidentified substances (hereafter called xe2x80x9cwaxesxe2x80x9d due to their physical characteristics); (2) free sterol and stanols (hereafter called xe2x80x9csterolsxe2x80x9d); and (3) a group mainly composed of fatty alcohol and sterol esters (hereafter called xe2x80x9cpitchxe2x80x9d due to the dark color caused by the presence of compounds of lignin degradation and oxidized compounds).
In the present invention, the separation of waxes, sterols and pitch from raw material is achieved by distilling the mixture in one or more short path distillation columns, also called molecular distillation columns.
To separate waxes, the raw material can be distilled under soft conditions in a system compound by a short path distillation column. If desried, a system with two or more short path distillation columns can also be used. In a multicolumn system, the distillate of the first column is used to feed a second column and the distillate of the second column is used to feed a third column and so on. The distillate becomes increasingly stripped of sterols and esters.
To separate pitch, the raw material can be distilled under mild conditions in a system composed by a short path distillation column. If desired, a system with two or more short path distillation columns can also be used. In a multicolumn system, the residue of the first column is used to feed a second column and the residue of the second column is used to feed a third column and so on. The residue becomes increasingly stripped of sterols and waxes.
One of the objectives of the present invention is to provide a method to produce an essentially sterol and pitch free wax. This method includes the steps of: (1) distilling the raw material in a short path distillation column. For this, the raw material that is solid at room temperature is melted at between 70 and 100xc2x0 C. until it is liquefied. In this condition, it is fed to a short path distillation column at a temperature between 100 and 200xc2x0 C. and at a pressure between 0.01 and 5 mbar. This is to produce a distillate whose weight is between 35 and 55% in weight of the feed raw material weight and to produce a residue whose weight is between 45 and 65% in weight of the feed raw material weight. The distillate contains not less than 70% in weight of free fatty alcohols in relation to the content of these alcohols in the raw material. (2) Collecting the essentially sterol and pitch free distillate or wax. To do this, the residence time of the distillate in the column is lesser than approximately 15 minutes, but it preferably lesser than 5 minutes.
Another objective of the present invention is to provide a method to produce an essentially sterol and pitch free wax. This method includes the steps of: (1) distilling the raw material in a first short path distillation column. For this, the raw material that is solid at room temperature is melted at between 70 and 100xc2x0 C. until it is liquefied. In this condition, it is fed to a short path distillation column at a temperature between 200 and 300xc2x0 C. and at a pressure between 0.01 and 5 mbar. This is done to produce a first distillate whose weight is between 70 and 90% in weight of the feed raw material weight and to produce a first residue whose weight is between 10 and 25% in weight of the feed raw material weight. The distillate contains not less than 70% in weight of free fatty alcohols in relation to the content of these alcohols in the raw material. To do this separation, the residence time of the distillate in the column is lesser than approximately 15 minutes, but preferably lesser than 5 minutes. (2) Collecting the first distillate. (3) Distilling the first distillate in a second short path distillation column at a temperature between 100 and 200xc2x0 C. and at a pressure between 0.01 and 5 mbar. This is done to produce a second distillate whose weight is between 45 and 65% in weight in relation to the first distillate weight and a second residue whose weight is between 35 and 55% in weight in relation to the first distillate. To do this separation, the residence time of the distillate in the column is lesser than approximately 15 minutes, but it is preferred lesser than 5 minutes. (4) Collecting the second essentially sterol and pitch free distillate or wax.
Another objective of the present invention is to provide a method to produce a concentrate of sterols essentially free of wax and pitch. This method includes the steps of: (1) Distilling the raw material in a first short path distillation column. For this, the raw material that is solid at room temperature, is melted down between 70 and 100xc2x0 C. until it is liquefied. In this condition, it is fed to a short path distillation column at a temperature between 200 and 300xc2x0 C. and at a pressure between 0.01 and 5 mbar. This is to produce a first distillate whose weight is between 70 and 90% in weight of the feed raw material weight and to produce a first residue whose weight is between 10 and 25% in weight of the feed raw material weight. The distillate contains not less than 70% in weight of free sterols in relation to the content of these free sterols in the raw material. To do this separation, the residence time of the distillate in the first column is less than approximately 15 minutes, but it preferably less than 5 minutes. (2) Collecting the first distillate, (3) Distilling the first distillate in a second short path distillation column at a temperature between 100 and 200xc2x0 C. and at a pressure between 0.01 and 5 mbar. This is to produce a second distillate whose weight is between 45 and 65% in weight in relation to the first distillate weight and a second residue whose weight is between 35 and 55% in weight in relation to the first distillate. To do this separation, the residence time of the distillate in the second column is less than approximately 15 minutes, but it is preferably less than 5 minutes. (4) Collecting the second residue which is composed of free sterols essentially free of wax and pitch, that is a sterol concentrate.
Another method to achieve the former objective includes the steps of (1) Distilling the raw material in a short path distillation column. For this, the raw material that is solid at room temperature is melted at between 70 and 100xc2x0 C. until it is liquefied. In this condition, it is fed to a first short path distillation column at a temperature between 100 and 200xc2x0 C. and at a pressure between 0.01 and 5 mbar. This is to produce a first distillate whose weight is between 40 and 55% in weight of the feed raw material weight and to produce a first residue whose weight is between 45 and 60% in weight of the feed raw material weight. The first residue contains not less than 70% in weight of free sterols in relation to the content of these free sterols in the raw material. To do this separation, the residence time of the distillate in the first column is lesser than approximately 15 minutes, but it is preferred lesser than 5 minutes. (2) Collecting the first residue. (3) Distilling the first residue in a second short path distillation column at a temperature between 200 and 300xc2x0 C. and at a pressure between 0.01 and 5 mbar. This is to produce a second distillate whose weight is between 45 and 65% in weight in relation to the first distillate weight and a second residue whose weight is between 35 and 55% in weight in relation to the first distillate. To do this separation, the residence time of the distillate in the first column is lesser than approximately 15 minutes, but it is preferably less than 5 minutes. (4) Collecting the second distillate or free sterols essentially free of wax and pitch, that is a sterol concentrate.
Another objective of the present invention is to provide a method to produce an pitch essentially free of wax and sterols. This method includes the steps of: (1) Distilling the raw material in a short path distillation column. For this, the raw material that is solid at room temperature is melted at between 70 and 100xc2x0 C. until it is liquefied. In this condition, it is fed to a short path distillation column at a temperature between 200 and 300xc2x0 C. and at a pressure between 0.01 and 5 mbar. This is to produce a distillate whose weight is between 75 and 90% in weight of the feed raw material weight and to produce a residue whose weight is between 10 and 25% in weight of the feed raw material weight. (2) Collecting the essentially sterol and wax free pitch residue. To do this separation, the residence time of the distillate in the column is less than approximately 15 minutes, but it is preferably less than 5 minutes.
Another objective of the present invention is to provide a method to produce pitch essentially free of wax and sterols. This method includes the steps of: (1) Distilling the raw material in a short path distillation column. For this, the raw material that is solid at room temperature is melted down at between 70 and 100xc2x0 C. until it is liquefied. In this condition, it is fed to a first short path distillation column at a temperature between 100 and 200xc2x0 C. and at a pressure between 0.01 and 5 mbar. This is to produce a first distillate whose weight is between 40 and 55% in weight of the feed raw material weight and to produce a first residue whose weight is between 45 and 60% in weight of the feed raw material weight. To do this separation, the residence time of the distillate in the first column is less than approximately 15 minutes, but it is preferably less than 5 minutes. (2) Collecting the first residue. (3) Distilling the first residue in a second short path distillation column at a temperature between 200 and 300xc2x0 C. and at a pressure between 0.01 and 5 mbar. This is to produce a second distillate whose weight is between 45 and 65% in weight in relation to the first distillate weight and a second residue whose weight is between 35 and 55% in weight in relation to the first distillate. To do this separation, the residence time of the distillate in the first column is less than approximately 15 minutes, but it is preferably less than 5 minutes. (4) Collecting the second residue or pitch essentially free of wax and sterols.
Another objective of the present invention is to provide a method to produce a composition of sterols and fatty acids from the pitch. This method includes the steps of: (1) Hydrolyzing the pitch obtained through the methods described above in an alkaline medium, preferably an aqueous or alcoholic solution of sodium or potassium hydroxide or pure ammonia or in an aqueous solution in presence of an organic solvent, preferably an aliphatic or aromatic hydrocarbon, at a temperature between 100 and 300xc2x0 C. and for a period of time sufficient for producing the hydrolysis of pitch esters. (2) Cooling down the mixture. (3) Separating the organic phase. (4) Washing the organic phase with an aqueous solution of ethanol or methanol. (5) Desolventizing the washed organic phase to obtain a composition of free sterols and fatty alcohols. If desired, this composition can be added to the raw material to obtain enriched raw material or added to a sterol concentrate. Alternatively, the hydrolysis can be carried out without the presence of an organic solvent. In this case, once the pitch is hydrolyzed, the solvent is added, extracting the alcohols and sterols of the hydrolyzed substance, and then the method is continued as described above.
Another objective of the present invention is to provide a method to produce a sterol composition with a sterol content of not less than 90% in weight in relation to such composition weight. This method includes the steps of: (1) Mixing the sterol fraction from the second short path distillation column with acetone, methyl ethyl ketone, methanol or ethanol or a mixture thereof. (2) Agitating at room temperature or refluxing this mixture. (3) Cooling down the mixture to a temperature of approximately xe2x88x9220 to 20xc2x0 C. (4) Separating the crystals produced during the cooling stage. (5) Desolventizing the crystals.
The described technique is normally used to crystallize sterols of raw materials with a sterol content lower than 50% in weight, although it is also applied to raw materials that have a higher sterol content.
For the sterol concentrates obtained through the methods described in the present invention, there is another method to obtain almost pure sterols which includes the steps of: (1) Mixing the concentrate with acetone or another solvent. (2) Stirring at low temperature. (3) Separating the solids from the mother liquor, for example, through filtration. (4) Desolventizing the solids, which is just a simple wash of the concentrate at a low temperature with a solvent. This process is only possible for products of the present invention, where the sterol content is so high that it is better washing them instead of recrystallizing them.
Another objective of the present invention is to provide a method to produce a fatty alcohol concentrate, between 20 and 26 carbons, with an alcohol content not lower than 75% in weight in relation to the alcohol concentrate weight. This procedure includes the steps of: (1) Mixing the wax from a first column or a second column with a solvent, preferably an aliphatic or aromatic hydrocarbon. (2) Refluxing this mixture. (3) Cooling down this mixture. (4) Separating the crystals produced during the cooling stage. (5) Desolventizing the crystals.
Another objective of the present invention is to provide a method to produce an essentially pitch free wax and free sterol mixture. This method includes the steps of: (1) Distilling the raw material in a short path distillation column. For this, the raw material that is solid at room temperature is melted at between 70 and 100xc2x0 C. until it is liquefied. In this condition, it is fed to a short path distillation column at a temperature between 200 and 300xc2x0 C. and at a pressure between 0.01 and 5 mbar. This is to produce a distillate whose weight is between 75 and 90% in weight of the feed raw material weight and to produce a residue whose weight is between 10 and 25% in weight of the feed raw material weight. (2) Collecting the essentially pitch free distillate. To do this separation, the residence time of the distillate in the column is less than approximately 15 minutes, but it is preferably less than 5 minutes.
Another objective of the present invention is to provide a method to produce an essentially wax and pitch free sterol concentrate. This method includes the steps of: (1) Mixing the first distillate from a first short path distillation column with acetone, methyl ethyl ketone, methanol or ethanol or a mixture thereof. (2) Refluxing the mixture. (3) Cooling down the mixture to a temperature of approximately xe2x88x9220 to 20xc2x0 C. (4) Separating the crystals produced during the cooling stage. (5) Desolventizing the crystals.
Another objective of the present invention is to provide a method to produce an essentially sterol and pitch free wax concentrate. This method includes the steps of: (1) Mixing the first distillate of a first short path distillation column with acetone, methyl ethyl ketone, methanol or ethanol or a mixture thereof. (2) Refluxing the mixture. (3) Cooling down the mixture to a temperature of approximately xe2x88x9220 to 20xc2x0 C. (4) Separating the crystals produced during the cooling stage. (5) Desolventizing the mother liquor to recover a wax concentrate.
Another objective of the present invention is to provide a method to produce an essentially sterol and pitch free fatty alcohols. This method includes the steps of: (1) Mixing the first distillate of a first short path distillation column with acetone, methyl ethyl ketone, methanol or ethanol or a mixture thereof. (2) Refluxing the mixture. (3) Cooling down the mixture to a temperature of approximately xe2x88x9220 to 20xc2x0 C. (4) Separating the crystals produced during the cooling stage. (5) Desolventizing the mother liquor. (6) Dissolving the residual solid of the disolvenation stage with hexane, heptane, toluene, xylene or a mixture thereof. (7) Refluxing this mixture. (8) Cooling down the mixture to a temperature of approximately between xe2x88x9220 and 20xc2x0 C. (9) Separating the crystals produced during the cooling stage. (10) Desolventizing the crystals.
Another objective of the present invention is to provide a method to produce an essentially wax and pitch free sterol concentrate. This method includes the steps of: (1) Mixing the first residue of a first short path distillation column with acetone, methyl ethyl ketone, methanol or ethanol or a mixture thereof (2) Agitating at room temperature or refluxing the mixture. (3) Cooling down the mixture to a temperature of approximately xe2x88x9220 to 20xc2x0 C. (4) Separating the crystals produced during the cooling stage. (5) Desolventizing the crystals.
Another objective of the present invention is to provide a method to produce an essentially wax and sterol free pitch. This method includes the steps of: (1) Mixing the first residue of a first short path distillation column with acetone, methyl ethyl ketone, methanol or ethanol or a mixture thereof. (2) Refluxing the mixture. (3) Cooling down the mixture to a temperature of approximately xe2x88x9220 to 20xc2x0 C. (4) Separating the crystals produced during the cooling stage. (5) Desolventizing the mother liquor to obtain a pitch concentrate.
The pitch obtained through the methods described in the present invention can be conveniently purified or bleached to obtain an ester concentrate suitable for an alimentary utilization.
For that, the dark colored pitch can be distilled in a short path distillation column with the evaporator at a temperature of or higher than 250xc2x0 C. and the condenser at a temperature between 150 and 200xc2x0 C. and a pressure between 0.01 and 5 mbar. It has been surprisingly discovered that the distillate is light or it has a light amber color in those conditions, and the dark, oxidized or degraded matter remains in the column residue.
Another way to purify or bleach the pitch is the adsorption of the dark impurities with activated carbon or another adsorbent. The methods to carry out the bleaching are going to be described in the examples.
Of course, if desired, the pitch can also be bleached prior to its hydrolysis to produce free sterols, stanols or fatty alcohols.
The terms xe2x80x9cessentially freexe2x80x9d are understood as follows:
Essentially pitch free wax: Fraction of the raw material with a content of fatty alcohol esters and sterol esters lower than 20% in weight of esters in relation to the content of these esters in the raw material and a content of fatty alcohols not lower than 70% in weight of these alcohols in relation to the content of these alcohols in the raw material.
Essentially sterol free wax: Fraction of the raw material with a content of free sterols lower than 20% in weight of free sterols in relation to the content of sterols in the raw material and a content of fatty alcohols not lower than 70% in weight of these alcohols in relation to the content of these alcohols in the raw material.
Essentially pitch free sterols: Fraction of the raw material with a content of fatty alcohol esters and sterol esters lower than 20% in weight of esters in relation to the content of these esters in the raw material and a content of free sterols and stanols not lower than 70% in weight of these free sterols and stanols in relation to the content of these free sterols in the raw material.
Essentially wax free sterols: Fraction of the raw material with a content of free fatty alcohols lower than 20% in weight of these alcohols in relation to the content of these alcohols in the raw material and a content of free sterols and stanols not lower than 70% in weight of these free sterols and stanols in relation to the content of these free sterols in the raw material.
Essentially wax free pitch: Fraction of the raw material with a content of free fatty alcohols lower than 20% in weight of these free alcohols in relation to the raw material and a content of alcohol and sterol esters not lower than 70% in weight of these alcohols in relation to the content of these alcohols in the raw material.
Essentially sterol free pitch: Fraction of the raw material with a content of free sterols and stanols lower than 20% of the content of these free sterols and stanols in relation to the content of these free sterols and stanols in the raw material and a content of fatty alcohol and sterol esters not lower than 70% in weight of these alcohols in relation to the content of these alcohols in the raw material.